GSTM1 and chronic kidney disease: Patients who suffered from bleeding complications presented with a significantly lower Hb (10.9 vs. 12.2 g/dl; p < 0.01) and higher creatinine levels (1.38 vs. 1.10 mg/dl; p = 0.03), and showed a higher prevalence of advanced chronic kidney disease (GFR < 45 ml/m2) (63.3% vs. 42.6%; p = 0.04) at baseline.